Genesis 1:29 and 30 have been widely translated from their original Hebrew as follows:
29 Then God said, "Behold, I have given you every plant yielding seed that is on the surface of all the earth, and every tree which has fruit yielding seed; it shall be food for you; 30 and to every beast of the earth and to every bird of the sky and to every thing that moves on the earth which has life, I have given every green plant for food''; and it was so.
I am now in contact with a Hebrew scholar who tells me that he believes these verses are widely mistranslated. He says he believes they should be translated as follows:
29 Then God said, "Behold, I have given you every plant yielding seed that is on the surface of all the earth, and every tree which has fruit yielding seed; it shall be food for you; 30 and every beast of the earth and every bird of the sky and every thing that moves on the earth which has life, I have given you, just as every green plant, for food''; and it was so.
If his translation of these verses is correct, then Genesis 1:30 does not refer to the diet of animals at all, and in fact actually teaches that God created mankind as omnivores.